This invention relates to a simple counterweight construction for a sealed compressor.
Sealed compressors are utilized in most refrigerant compression applications. One well known type of sealed compressor is a scroll compressor. In a scroll compressor, first and second scroll elements are each formed with a base and a generally spiral wrap extending from the base. The wraps interfit to define compression chambers. One of the two scroll members is caused to orbit relative to the other.
Scroll compressors are formed to have a counterweight associated with their drive shaft. The counterweight is positioned to account for weight imbalance during operation of the scroll compressor.
Historically, counterweights were relatively large items. As an example, FIG. 1 shows a prior art sealed compressor 20. The compressor incorporates a non-orbiting scroll member 22 and orbiting scroll 24. The scroll members each include wraps 25, which interfit to define compression chambers. An electric motor 30 includes a stator 32 and a rotor 34. As known, the stator has windings 36 at each axial end. The rotor 34 has an end ring 38 at each end. As can be appreciated in FIG. 1, the upper end ring stops at a vertical position beneath the vertically uppermost portion of the windings 36. A relatively massive counterweight 40 is shown in FIG. 1. The counterweight 40 requires a good deal of space.
More recently, the assignee of the present application has developed a thin, stamped counterweight. This counterweight is shown for example in U.S. Pat. No. 6,247,907. While the counterweight of this patent is successful, and requires less axial space than the prior art of FIG. 1, it would still be desirable to further simplify the counterweight.
The instant application includes a thin counterweight which is formed from a relatively flat sheet. The relatively flat sheet is a very simple part to manufacture, and will require little axial space when assembled. In another aspect of this invention, the counterweight is attached to the upper end ring of the rotor. Preferably, the end ring extending vertically upwardly beyond the vertically uppermost part of the stator windings.
The present invention thus provides a unique counterweight which is simpler to manufacture than the prior art, and which requires little axial space.